Petri dish



FIG. 1 is a perspective view of a petri dish showing my new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a side elevation thereof;

FIG. 4 is a bottom plan view thereof;

FIG. 5 is a fragmentary cross-section taken on line 5--5 of FIG. 1; and

FIG. 6 is a top plan view of a modified embodiment of the petri dish illustrated in FIGS. 1 and 2. 

The ornamental design for a petri dish, substantially as shown and described. 